scholarly journals Influence of Temperature on Water and Aqueous Glucose Absorption Spectra in the Near- and Mid-Infrared Regions at Physiologically Relevant Temperatures

2003 ◽  
Vol 57 (1) ◽  
pp. 28-36 ◽  
Author(s):  
Peter Snoer Jensen ◽  
Jimmy Bak ◽  
Stefan Andersson-Engels
Keyword(s):  
Absorption Spectra ◽  
Near Infrared ◽  
Pure Water ◽  
Glucose Absorption ◽  
Diagnostic Methods ◽  
Effect Of Temperature ◽  
Difference Spectra ◽  
Absorption Bands ◽  
Mid Infrared ◽  
Temperature Range

Near- and mid-infrared absorption spectra of pure water and aqueous 1.0 g/dL glucose solutions in the wavenumber range 8000–950 cm−1 were measured in the temperature range 30–42 °C in steps of 2 °C. Measurements were carried out with an FT-IR spectrometer and a variable pathlength transmission cell controlled within 0.02 °C. Pathlengths of 50 μm and 0.4 mm were used in the mid- and near-infrared spectral region, respectively. Difference spectra were used to determine the effect of temperature on the water spectra quantitatively. These spectra were obtained by subtracting the 37 °C water spectrum from the spectra measured at other temperatures. The difference spectra reveal that the effect of temperature is highest in the vicinity of the strong absorption bands, with a number of isosbestic points with no temperature dependence and relatively flat plateaus in between. On the basis of these spectra, prospects for and limitations on data analysis for infrared diagnostic methods are discussed. As an example, the absorptive properties of glucose were studied in the same temperature range in order to determine the effect of temperature on the spectral shape of glucose. The change in water absorption associated with the addition of glucose has also been studied. An estimate of these effects is given and is related to the expected level of infrared signals from glucose in humans.

Use of Near-Infrared–Mid-Infrared Dual-Wavelength Spectrometry to Obtain Two-Dimensional Difference Spectra of Sesame Oil as Inactive Drug Ingredient

2020 ◽  
pp. 000370282096919
Author(s):  
Masahiro Watari ◽  
Akifumi Nagamoto ◽  
Takuma Genkawa ◽  
Shigeaki Morita
Keyword(s):  
Room Temperature ◽  
Near Infrared ◽  
Sesame Oil ◽  
Partial Least Square ◽  
Dual Wavelength ◽  
Two Dimensional ◽  
Difference Spectra ◽  
Mid Infrared ◽  
Starting Point ◽  
Drug Ingredient

The present study has investigated the transformation of sesame oil kept at low temperature during a definite period of time for refinement (called winterization) as an inactive drug ingredient by using two-dimensional difference spectra (2D-DS) analysis of spectra collected using a near-infrared (NIR) and mid-infrared (MIR) dual-wavelength spectrometer (NIR–MIR-DWS). The NIR and MIR spectra were measured nearly simultaneously from samples of sesame oil before and after winterization. The difference spectrum analysis of the obtained NIR–MIR data elucidated that, after the winterization process, the absorbances at peaks attributed to C=O, C=C, and OH groups decrease while the absorbances arising from the main chain (CH2) increase. The result indicated the removal of lignan and the fatty acids with relatively short main chains. Moreover, sesame oil unwinterized was cooled from room temperature to near 1 ℃ and subsequently warmed to room temperature. And the cycle was repeated two times. Real-time monitoring during the cooling and warming processes were carried out using the NIR-MIR-DWS. The prediction results obtained from partial least square calibration model for the temperature suggests that there are subtle differences in the oil composition between the first cooling process and after the warming and cooling cycle. For the more detailed analysis, the 2D-DS method is proposed. The results of the analyses using 2D-DS revealed that the starting point of the transformation is around 15 ℃. It can be estimated that sesame oil is mainly transformed by the first cooling down. Moreover, it was implied that the structure of methylene (CH2) was significantly related to the modifications in sesame oil with temperature change. A series of experimental results elucidated that the winterization of sesame oil removed its impurities and stabilized its conditions. These results are probably the first report on the effect of the winterization process on sesame oil.

scholarly journals Near-Infrared Studies of Glucose and Sucrose in Aqueous Solutions: Water Displacement Effect and Red Shift in Water Absorption from Water-Solute Interaction

2013 ◽  
Vol 67 (2) ◽  
pp. 171-180 ◽  
Author(s):  
Youngeui Jung ◽  
Jungseek Hwang
Keyword(s):  
Aqueous Solutions ◽  
Near Infrared ◽  
Hydration Shell ◽  
Glucose Absorption ◽  
Water Soluble ◽  
Red Shift ◽  
Water Molecules ◽  
Water Displacement ◽  
Absorption Bands ◽  
Displacement Effect

We used near infrared spectroscopy to obtain concentration dependent glucose absorption spectra in aqueous solutions in the near-infrared range (3800–7500 cm−1). Here we introduce a new method to obtain reliable glucose absorption bands from aqueous glucose solutions without measuring the water displacement coefficients of glucose separately. Additionally, we were able to extract the water displacement coefficients of glucose, and this may offer a new general method using spectroscopy techniques applicable to other water-soluble materials. We also observed red shifts in the absorption bands of water in the hydration shell around solute molecules, which comes from the contribution of the interacting water molecules around the glucose molecules in solutions. The intensity of the red shift gets larger as the concentration increases, which indicates that as the concentration increases more water molecules are involved in the interaction. However, the red shift in frequency does not seem to depend significantly on the concentration. We also performed the same measurements and analysis with sucrose instead of glucose as solute and compared.

scholarly journals NIR Absorbance Characteristics of Deoxynivalenol and of Sound and Fusarium-Damaged Wheat Kernels

2009 ◽  
Vol 17 (4) ◽  
pp. 213-221 ◽  
Author(s):  
Kamaranga H.S. Peiris ◽  
Michael O. Pumphrey ◽  
Floyd E. Dowell
Keyword(s):  
Absorption Spectra ◽  
Near Infrared ◽  
Peak Height ◽  
Second Derivative ◽  
Absorption Bands ◽  
Derivative Spectra ◽  
Nir Absorption ◽  
Second Derivative Spectra ◽  
Food Reserves ◽  
Wheat Kernels

The near infrared (NIR) absorption spectra of deoxynivalenol (DON) and single wheat kernels with or without DON were examined. The NIR absorption spectra of 0.5–2000 ppm of DON in acetonitrile were recorded in the 350–2500 nm range. Second derivative processing of the NIR spectra and spectral subtractions showed DON absorption bands at 1408 nm, 1904 nm and 1919 nm. NIR spectra of sound and Fusarium-damaged kernels were also acquired using two instruments. Subtraction of average absorption spectra and second derivative spectra were evaluated to identify different NIR signatures of the two types of kernel. Differences in peak height and positions of the NIR absorption bands of the kernels were noted. At 1204 nm, 1365 nm and 1700 nm, the differences were in the heights of the absorption peaks. Such differences may be attributed to changes in the levels of grain food reserves such as starches, proteins and lipids and other structural compounds. Shifts in absorption peak positions between the two types of kernels were observed at 1425–1440 nm and 1915–1930 nm. These differences may arise from other NIR active compounds, such as DON, which are not common for the two types of kernel. Since the NIR absorption of DON may have contributed to the shifts between sound and Fusarium-damaged kernels, this study indicates the potential for NIR spectrometry to evaluate Fusarium damage in single kernels based on the DON levels.

Optical Anisotropy of RMnO3 Manganites in the Range of 4f-4f Transitions

2010 ◽  
Vol 168-169 ◽  
pp. 549-552 ◽  
Author(s):  
Natalia N. Loshkareva ◽  
Elena V. Mostovshchikova ◽  
A.S. Moskvin ◽  
Sergey V. Naumov ◽  
Natalia V. Kostromitina ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Optical Anisotropy ◽  
Polarized Light ◽  
Transparency Window ◽  
Infrared Range ◽  
Spectral Features ◽  
Mid Infrared ◽  
Temperature Range ◽  
Hexagonal Manganites

Optical absorption of orthorhombic and hexagonal manganites RMnO3 (R= Pr3+, Gd3+, Sm3+, Eu3+, Ho3+, Tm3+, Er3+, and Yb3+) were studied in polarized light in the near- and mid-infrared range for the temperature range 80 - 300 K. Several spectral features associated with 4f-4f transitions of R3+ ions were found in the transparency window of RMnO3. Anisotropy of the absorption spectra in the range of multiplet 4f-4f transitions and changes in populations of the multiplet levels with temperature were observed.

Effect of composition on the thermal properties and spontaneous emission probabilities of Tm3+-doped TeO2–LiCl glass

2001 ◽  
Vol 16 (5) ◽  
pp. 1381-1388 ◽  
Author(s):  
G. özen ◽  
B. Demirata ◽  
M. L. öveçoğlu
Keyword(s):  
Thermal Properties ◽  
Spontaneous Emission ◽  
Near Infrared ◽  
Transition Probabilities ◽  
Glass Composition ◽  
Ground Level ◽  
Radiative Transition ◽  
Absorption Bands ◽  
Temperature Range ◽  
Absorption Measurements

The effect of composition on the thermal properties and the spontaneous emission probabilities of various 0.5 mol% Tm2O3 containing (1 − x)TeO2 + (x)LiCl glasses were investigated using differential thermal analysis (DTA) and ultraviolet–visible– near-infrared (UV/VIS/NIR) absorption measurements. DTA curves of the samples were obtained in the 23–600 °C temperature range with a heating rate of 10 °C/min. The value of the glass transition temperature Tg and the crystallization temperatureTc were found to vary with the glass composition. Melting was not observed for the glasses containing less than 50 mol% LiCl in this temperature range. However, a melting peak was observed at Tm = 401 °C for the glasses having higher than 50 mol% LiCl, which were also found to be moisture-sensitive. Absorption measurements in the UV/VIS/NIR region were used to determine spontaneous emission probabilities for the 4f−4f transitions of Tm3+ ions. Six absorption bands corresponding to the absorption of the 1G4, 3F2, 3F3, 3F4, 3H5, and 3H4 levels from the 3H6 ground level were observed. An integrated absorption cross section of each band, except that of 3H5 level, was found to vary with the glass composition. The role of the Judd–Ofelt parameters and therefore the effect of the glass composition on the radiative transition probabilities for the metastable levels of Tm3+ ions are discussed in detail.

Visible Luminescence Properties of Sm3+ Doped Magnesium Bismuth Phosphate Glasses

2016 ◽  
Vol 675-676 ◽  
pp. 405-408 ◽  
Author(s):  
Narong Sangwaranatee ◽  
Jakrapong Kaewkhao ◽  
Natthakridta Chanthima
Keyword(s):  
Absorption Spectra ◽  
Near Infrared ◽  
Infrared Region ◽  
Phosphate Glasses ◽  
Excitation Wavelength ◽  
Absorption Bands ◽  
Visible Luminescence ◽  
Yellow Color ◽  
Bismuth Phosphate ◽  
Quenching Method

In this research, the magnesium bismuth phosphate glasses doped with different concentration of Sm2O3 have been prepared using the melt quenching method at 1200 °C. Magnesium bismuth phosphate glasses are clear, homogenous and increased yellow color with increasing the concentration of Sm2O3. Physical and optical properties of glass samples were investigated. The results show that, the density and molar volumes were increased with increasing the concentration of Sm2O3. The absorption spectra in the wavelength range at 200 - 2500 nm was observed. It was found that the absorption bands have nine peaks with corresponding to 401, 439, 472, 945, 1081, 1231, 1378, 1480 and 1533 nm. Absorption bands at 401 and 1231 nm are highest absorption spectra in visible and near infrared region, respectively. For the luminescence spectrum of glass samples has shown four emission transitions at 562 (green), 598 (orange), 664 (red) and 705 nm with excitation wavelength at 401 nm. The wavelength at 401 and 598 nm has shown highest intensity of excitation and emission wavelength, respectively.

Near infrared spectra of some cobalt(II) compounds

1968 ◽  
Vol 21 (7) ◽  
pp. 1775
Author(s):  
DP Graddon ◽  
GM Mockler
Keyword(s):  
Absorption Band ◽  
Absorption Spectra ◽  
Metal Atom ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Infrared Region ◽  
Absorption Bands ◽  
Heterocyclic Base ◽  
Near Infrared Spectra ◽  
Near Infrared Region

Absorption spectra of compounds CoX2B2 and CoX2B4 (X = Cl, Br, I, or NCS; B = a heterocyclic base) have been obtained by reflectance and in solution in the near infrared region between 1000 and 2000 mμ. The spectra are characteristic of the stereochemistry of the metal atom: octahedral compounds have a single absorption band near 1100 mμ, e < 10; tetrahedral compounds have three overlapping absorption bands near 1100,1400, and 1700 mp, 30 < < 150. Comparisons are made with previously observed spectra of octahedral and tetrahedral species of the types CoL2+6 and CoX2-4.

Infrared Studies of the Double Acceptor Zinc in Silicon

1989 ◽  
Vol 163 ◽  
Author(s):  
A. Dörnen ◽  
R. Kienle ◽  
K. Thonke ◽  
P. Stolz ◽  
G. Pensl ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Charge State ◽  
Crystal Field ◽  
Absorption Spectra ◽  
Ground State ◽  
Near Infrared ◽  
Mid Infrared ◽  
Absorption Studies ◽  
Infrared Studies ◽  
Neutral Charge State

AbstractIn the present paper, optical absorption studies on the neutral charge state of the double acceptor zinc in silicon are presented. Measurements were carried out in the mid infrared (MIR) and in the near infrared (NIR) region. The MIR absorption spectra show the excitation series of an effective-masslike hole, from which the Zn° level position is calculated to be at Ev + 319. 1 meV. A splitting of the ground state into 3 sublevels is assigned to hole-hole coupling and crystal-field splitting. Absorption spectra obtained in the NIR are interpreted in terms of an A° X-type bound exciton.

Temperature Effects on a Fiber-Optic Evanescent Wave Absorption Sensor

1994 ◽  
Vol 48 (3) ◽  
pp. 387-393 ◽  
Author(s):  
G. L. Klunder ◽  
J. BÜrck ◽  
H.-J. Ache ◽  
R. J. Silva ◽  
R. E. Russo
Keyword(s):  
Absorption Spectra ◽  
Evanescent Wave ◽  
Near Infrared ◽  
Chemical Sensor ◽  
Fiber Optic ◽  
Absorption Bands ◽  
Wave Absorption ◽  
Influence Of Temperature On ◽  
Background Absorption ◽  
Cladding Material

A coiled fiber-optic chemical sensor has proven to be effective for the remote detection of volatile organic compounds, such as trichloroethylene (TCE), 1,1-dichloroethylene (DCE), and gasoline, in aqueous solutions. The analyte diffuses into the hydrophobic cladding and evanescent wave absorption spectra are measured in the near-infrared (1600–1850 nm) without the presence of the water absorption bands. In order for fiberoptic chemical sensors to operate effectively in remote environments, the influence of temperature on the sensor response must be known. The C-H bonds of the polysiloxane cladding material also have absorption bands in the near-infrared (NIR). Changes in temperature will change the density (i.e., concentration of C-H bonds) and refractive index of the cladding. Due to these effects, a temperature change of only 3°C from the reference has been shown to significantly alter the background absorbance. The temperature-dependent background absorption is found to be linear with the slope, and the values are proportional to the absorption coefficient of the cladding material. The intercept of the absorbance vs. temperature plot is found to follow the first derivative of the fiber sensor transmission spectrum. Evanescent wave absorption spectra of TCE solutions have been corrected for temperature.

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